New parsing error

[rpgoldman]

pandaPIgrounder gives me an error as follows:

Reading input from /io/escape-p1.htn.
General Options
  Print timings: false
  Quiet mode: false
Inference Options
  H2 mutexes: false
  FAM groups: false
Transformation Options
  Add zero-cost no-op to empty methods: true
  Remove duplicate actions: true
  Remove useless literals: true
  Expand abstract tasks with one method: true
  Remove empty method preconditions: true
  Two regularisation: false
  Compile negative SAS variables: false
Runtime Optimisations
  Hierarchy Typing: true
  Future Caching: false
  Static Precondition Checking: false
Output Options
  Panda planner format: true
  HDDL: false
  SAS for Fast Downward (without hierarchy): false
Output Formatting Options
  Output only SAS+ variables: false
  SAS+ delete mode: as input
Input parse error: basic_ios::clear: iostream error
The error is at: __method_precondition_move-to-no-obstacle 7 7
Writing output to /io/output.sas.
Writing output to standard output.
Failed to read input data!

(the funny file names are because the grounder is running in a container)

the input item corresponding to this complaint seems to be:

#begin_task_name_number_of_original_variables_and_number_of_variables
__method_precondition_move-to-no-obstacle 7 7
#sorts_of_variables
2 5 5 5 5 1 6
#end_variables
#number_of_cost_statements
1
#begin_cost_statements
const 0
#end_cost_statements
#preconditions_each_predicate_and_argument_variables
4
5 0 1 2
27 1 2 3 4 5
2 5 3 4
3 0 6
#add_each_predicate_and_argument_variables
0
#conditional_add_each_with_conditions_and_effect
0
#del_each_predicate_and_argument_variables
0
#conditional_del_each_with_conditions_and_effect
0
#variable_constraints_first_number_then_individual_constraints
0
#end_of_task

Full input file is in this gist

[galvusdamor]

The actual error is a few lines above in the declaration of the action __method_precondition_goto-exit-move. One of its preconditions is 6 3 4 - but the predicate 6 (-at-agent, i.e. not at-agent) requires 3 arguments, not 2.

Note: the grounder's parser assumes that the formatting is correct and the parser does not check that the modeller actually specified the correct number of arguments. This is something to add for usability in the future.

[galvusdamor]

@rpgoldman I've added a couple of safety checks to the parser (correct number of arguments for predicates and tasks, names of predicates and tasks actually exist), too. This should prohibit a lot of such errors in the future.